// 防抖
export const debounce = (func, wait = 3000, immediate = true) => {
 let timeout = null;
 return function() {
  let context = this;
  let args = arguments;
  if (timeout) clearTimeout(timeout);
  if (immediate) {
   var callNow = !timeout; //点击第一次为true 时间内点击第二次为false 时间结束则重复第一次
   timeout = setTimeout(() => {
    timeout = null;
   }, wait); //定时器ID
   if (callNow) func.apply(context, args);
  } else {
   timeout = setTimeout(function() {
    func.apply(context, args);
   }, wait);
  }
 };
};
// 时间戳方案
export const throttleTime = (fn, wait = 2000) => {
 var pre = Date.now();
 return function() {
  var context = this;
  var args = arguments;
  var now = Date.now();
  if (now - pre >= wait) {
   fn.apply(context, args);
   pre = Date.now();
  }
 };
};
// 定时器方案
export const throttleSetTimeout = (fn, wait = 3000) => {
 var timer = null;
 return function() {
  var context = this;
  var args = arguments;
  if (!timer) {
   timer = setTimeout(function() {
    fn.apply(context, args);
    timer = null;
   }, wait);
  }
 };
};